Circuit Structure and Control Method to Reduce Size and Harmonic Distortion of Interleaved Dual Buck Inverter

A new circuit structure and control method for a high power interleaved dual-buck inverter are proposed. The proposed inverter consists of six switches, four diodes and two inductors, uses a dual-buck structure to eliminate zero-cross distortion, and operates in an interleaved mode to reduce the current stress of switch. To reduce the total harmonic distortion at low output power, the inverter is controlled using discontinuous-current-mode control combined with continuous-current-mode control. The experimental inverter had a power-conversion efficiency of 98.5% at output power = 1300 W and 98.3% at output power = 2 kW, when the inverter was operated at an input voltage of 400 V-DC, output voltage of 220 V-AC/60 Hz, and switching frequency of 20 kHz. The total harmonic distortion was < 0.66%, which demonstrates that the inverter is suitable for high-power dc-ac power conversion.11Ysciescopu

Requirements for a transformerless power conditioning system

Requirements for development of a Transformerless Power Conditioning Subsystem (TPCS) that will meet utility, manufacturer, and customer needs are detailed. Issues analyzed include current utility guidelines, safety and grounding issues that appear as local codes, various kinds of TPCS connections that can be developed, dc injection, and a brief survey of TPCS circuit topologies that will meet requirements. The major result is that a finite time exists for control operation before dc injection into the distribution transformer causes customer outage (on the order of seconds). This time permits the control system to sense a dc injection condition and remove the TPCS from the utility system. Requirements for such a control system are specified. A three wire connection will ensure balanced operation for customer loads and two wire connections caused average value dc to be injected into single phase loads. This type of connection also allows for the lowest array voltage. The conclusion is that requirements for a TPCS can be determined and that there are not showstopping issues preventing implementation. The actual design and topology of the TPCS was left for further study

The presentation of sustainable power source assets in the field of intensity age assumes an imperative job

DC to DC converters to interface lesser-voltage higher-control supply to the essential stock shows the most raised proficiency was practiced in the full-connect converter. Non-separated converters bury unified inductor help converters with essential voltage gain and furthermore converters hold lesser profitability, yet they huge in structure, even the quantity of latent parts is diminished. In like manner gives proficient utilization of semiconductor switches, have higher voltage yield and are prepared to work in lesser estimation of D interestingly with every single disconnected converter. High addition topologies are regularly outfitted with high voltage security structures. Few non-disengaged topologies gives voltage hang security circuits are pointless since capacitive fragments and circuit plan are progressed to work under higher information voltage and low power. That requires lesser qualities for convincing RAC obstruction and entomb partnered inductance dispersal to achieve more prominent adequacy of intensity change. Larger supply current needs extensive region of core area inter allied inductors

A comparative study of electric power distribution systems for spacecraft

The electric power distribution systems for spacecraft are compared concentrating on two interrelated issues: the choice between dc and high frequency ac, and the converter/inverter topology to be used at the power source. The relative merits of dc and ac distribution are discussed. Specific converter and inverter topologies are identified and analyzed in detail for the purpose of detailed comparison. Finally, specific topologies are recommended for use in dc and ac systems

Control por histéresis para un inversor buck-dual conectado a la red

Single-phase inverters are widely used in different renewable energy applications. Although the full-bridge inverter is typically used, dual-buck inverters provide an important advantage, since they eliminate the shoot-through problems. However, solutions proposed in the literature require additional inductors, use linear controllers designed around an operation point, or cannot be used in grid-connected applications. This paper presents a hysteresis current control of a single-phase dual-buck full-bridge inverter for grid-connected active power injection. Includes the dynamical model in state variables, as well as analytical conditions to guarantee the evolution of the error dynamics in a set with boundaries defined by the designer. Moreover, the paper provides guidelines for the design of the dead band required for the transitions between the positive and negative semi-cycles (and vice-versa) of the grid voltage. Finally, simulation results validate the main features of the controller as well as the design of the dead band.Los inversores monofásicos son ampliamente usados en diferentes aplicaciones de energías renovables. Aunque típicamente se usa el inversor de puente completo, el inversor buck-dual provee una ventaja&nbsp; importante porque elimina el problema de posibles cortos-circuitos. Sin embargo, las soluciones reportadas en la literatura requieren inductores adicionales, usan controladores lineales diseñados para un punto de operación, o no se pueden usar en aplicaciones de conexión a la red. En este artículo se presenta un control por histéresis para un inversor monofásico buck-dual de puente completo con conexión a la red para inyección de corriente activa. En particular, se presenta el modelo matemático en variables de estado y se obtienen condiciones analíticas para garantizar la evolución de la dinámica de error dentro de un conjunto con límites establecido por el diseñador. Además, se discuten los elementos para diseñar la banda muerta requerida en la transición entre los semi-ciclos positivos y negativos de la tensión de la red. Finalmente, los resultados de simulación validan las principales características del controlador propuesto, así como el diseño de la banda muerta

PIC Control Dc To Dc Converter With Variable Input Voltage And Constant Output Voltage For Photovoltaic Integration

In recent years, attention towards renewable energy such as solar power had increased dramatically due to the awareness of energy crisis. A lot of solar power application systems had been designed. One of the most important solar power applications is to deliver the power produced by solar panel to local utility grid. A constant voltage should be obtained from solar panel in the design of this application system as solar panel is producing a fluctuating voltage level which depends on irradiation and temperature level. Therefore, a DC-DC boost converter is designed to step up the fluctuating solar panel voltage to a higher constant voltage. A microcontroller based DC-DC boost converter is proposed in this design. A PIC16F877 microcontroller is used and performs a voltage-feedback technique where it continuously tracks and measures the DC-DC boost converter output voltage and compares the measured value to a reference voltage. The differential compared value is used to produce a pulse-width-modulation signal. The signal is used to control a switch in the DC-DC boost converter. Simulation results describe the performance of the proposed design. Experimental work was carried out with the converter operating in continuous conduction mode with constant 24 V output voltage, 100 W output power, 20 kHz switching frequency and supplied from solar panel voltage. The experimental results show that the proposed design is able to produce a constant 24 V with efficiency more than 72.9% at 100 W load conditions

Advanced Control Techniques for Efficiency and Power Density Improvement of a Three-Phase Microinverter

Inverters are widely used in photovoltaic (PV) based power generation systems. Most of these systems have been based on medium to high power string inverters. Microinverters are gaining popularity over their string inverter counterparts in PV based power generation systems due to maximized energy harvesting, high system reliability, modularity, and simple installation. They can be deployed on commercial buildings, residential rooftops, electric poles, etc and have a huge potential market. Emerging trend in power electronics is to increase power density and efficiency while reducing cost. A powerful tool to achieve these objectives is the development of an advanced control system for power electronics. In low power applications such as solar microinverters, increasing the switching frequency can reduce the size of passive components resulting in higher power density. However, switching losses and electromagnetic interference (EMI) may increase as a consequence of higher switching frequency. Soft switching techniques have been proposed to overcome these issues. This dissertation presents several innovative control techniques which are used to increase efficiency and power density while reducing cost. Dynamic dead time optimization and dual zone modulation techniques have been proposed in this dissertation to significantly improve the microinverter efficiency. In dynamic dead time optimization technique, pulse width modulation (PWM) dead times are dynamically adjusted as a function of load current to minimize MOSFET body diode conduction time which reduces power dissipation. This control method also improves total harmonic distortion (THD) of the inverter output current. To further improve the microinverter efficiency, a dual-zone modulation has been proposed which introduces one more soft-switching transition and lower inductor peak current compared to the other boundary conduction mode (BCM) modulation methods. In addition, an advanced DC link voltage control has been proposed to increase the microinverter power density. This concept minimizes the storage capacitance by allowing greater voltage ripple on the DC link. Therefore, the microinverter reliability can be significantly increased by replacing electrolytic capacitors with film capacitors. These control techniques can be readily implemented on any inverter, motor controller, or switching power amplifier. Since there is no circuit modification involved in implementation of these control techniques and can be easily added to existing controller firmware, it will be very attractive to any potential licensees

Lightweight multiple output converter development

A high frequency, multiple output power conditioner was developed and breadboarded using an eight-stage capacitor diode voltage multiplier to provide +1200 Vdc, and a three-stage for -350 Vdc. In addition, two rectifier bridges were capacitively coupled to the eight-stage multiplier to obtain 0.5 and 0.65 a dc constant current outputs referenced to +1200 Vdc. Total power was 120 watts, with an overall efficiency of 85 percent at the 80 kHz operating frequency. All outputs were regulated to three percent or better, with complete short circuit protection. The power conditioner component weight and efficiency were compared to the equivalent four outputs of the 10 kHz conditioner for the 8 cm ion engine. Weight reduction for the four outputs was 557 grams; extrapolated in the same ratio to all nine outputs, it would be 1100 to 1400 grams

Power Electronic Converters for Single-Phase Grid Connected Photovoltaic System: An Overview

The Solar photovoltaic (PV) power system have achieved meteoric rise through the years. The uptake is not difficult to explain – a drop in cost of PV systems and spiraling electricity cost, have&nbsp; encouraged the end-user to lessen their bills by producing cheaper electricity and can generate revenue&nbsp; by feeding excess power back to the grid. The solar PV is intermittent in nature so it dependent on irradiance and ambient temperature. Power electronics technologies plays an important part for optimizing the energy harvesting from PV system. In order to get maximum extracted power and ensure the load is supplied with a good quality voltage, different dc-dc converters topologies and inverters configurations are used. This paper provides an overview of PV inverter configurations and DC-DC topologies to offer a useful insight and reference point for the researchers working in the field of photovoltaic system

Analysis of a new family of DC-DC converters with input-parallel output-series structure

There is an increasing trend of development and installation of switching power supplies due to their highly efficient power conversion, fast power control and high quality power conditioning for applications such as renewable energy integration and energy storage management systems. In most of these applications, high voltage conversion ratio is required. However, basic switching converters have limited voltage conversion ratio. There has been much research into development of high gain power converters. While most of the reported topologies focus on high gain and high efficiency, in this thesis, the input and output ripple currents and reliability are also considered to derive a new converter structure suitable for high step-up voltage conversion applications. High ripple currents and voltages at the input and output of dc-dc converters are not desirable because they may affect the operation of the dc source or the load. A number of converters operating in an interleaved manner can reduce these ripples. This thesis proposes a dc/dc switching converter structure which is capable of reducing the ripple problem through interleaved action, in addition to high gain and high efficiency voltage conversion. The thesis analyses the proposed converter structure through a dual buck-boost converter topology. The structure allows different converter topologies and combinations of them for different applications to be configured. The study begins with a motivation and a literature review of dc/dc converters. The new family of high step-up converters is introduced with an interleaved buck-boost as an example, followed by small-signal analysis. Experimental verifications, conclusions and future work are discussed